Electric switch assembly



Aug; 4, 1953 P. M. BYAM 2,647,968

I ELECTRIC SWITCH ASSEMBLY Filed 001;. 2, 1950 2 Sheefs-Sheet l" I \TVENTOR PETE/Q51. 5 MM BY 4wya ATTORNE Aug. 4, 1953 P. M. BYAM ELECTRIC SWITCH ASSEMBLY 2 Sheets-Sheet 2 [NVENTOR PETE/FM. 5X4? w W ATTORNJ Patented Aug. 4, 1953 ELECTRIC SWITCH ASSEMBLY Peter M. Byam, Rochester, N. Y., assignor to Fasco Industries, Inc., Rochester, N. Y., a corporation of New York Application October 2, 1950, Serial No. 187,850

1 Claim.

1 The present invention relates to improvements in an electric switch assembly and more particularly to improvements in a fluid operated switch assembly.

The primary object of the present invention is the provision of an electric switch assembly in which the switch arm members are accurately and readily mounted so that the switch assembly is especially adaptable to mass production.

Another object of the invention is cooperation between the switch arm members and the body member so that mere insertion and fastening of the terminal members accurately locates the switch arm members within said body member.

A further object of the invention is the provision of spaced chordal flats on the cylindrical wall of the body member and fiat outer edges on the switch arm members so that insertion and fastening of the terminal members holds the switch arm members with their ends in juxtaposition and electrically connected to respective switch arm members.

Still another object is the provision of a semicircular switch arm member which partially encircles a fluid operated actuating member for contact with the free end of a companion switch arm member.

Other and further objects of the invention will be apparent to those skilled in the art from the description which follows.

The aforementioned and other objects of the invention are embodied in an electric switch assembly comprising a body member provided with a recess having a cylindrical side wall and a pair of chordal flat portions in spaced relation therearound, a switch arm member including a mounting portion having a pair of fiat outer edges in spaced relation equal to the spacing of said chordal fiat portions and including a cantilever extending from one end of said mounting portion diametrically across said recess, a termi-' nal member havin a stem extending through one end of said mounting member to hold the fiat outer edges thereof against said chordal flat portions, a second switch arm member having a flat outer edge and having a free end for engaging the cantilever arm of the first mentioned switch arm member, an insulating spacer between said switch arm members, and a second terminal member having a stem extending through said switch arm members and said spacer and holdin the flat edge of said second switch arm member against one of said chordal flat portions. The first mentioned switch arm member is provided with a clearance hole for the stem of said second terminal member which facilitates assembly of the switch arm members and greatly simplifies connection to the respective terminal members. Also the heads of the terminal members are polygonal, preferably square, so that each head abuts one of the chordal flats to keep the terminal members from turning. In addition, the semi-circular form of one switch arm member partially encircles the centrally located actuating member for more compact arrangement and the formation of the switch arm members is such that by mere bending of the free ends of the switch arm members the switch assembly can be made a normally closed or normally open switch, as desired.

Reference is hereby made to the accompanying drawings wherein similar reference characters designate similar elements and wherein:

Fig. 1 is an axial cross-section of the normally closed form of the switch assembly according to the invention and is taken on line l-| of Fig. 2.

Fig. 2 is a bottom elevation of the switch assembly.

Fig. 3 is a plan elevation of the body member and switch arm members mounted therein for a normally closed switch assembly.

Fig. 4 is a plan elevation of one of the switch arm members.

Fig. 5 is a plan elevation of the other switch arm member.

Fig. 6 is a plan elevation of the body member and switch arm members mounted therein for a normally open switch assembly according to the invention.

Fig. 7 is an axial cross-section taken on the line 1-1 of Fig. 6 and showing the body memher and switch arms of the normally open switch assembly of the invention.

Figs. 8 and 9 are partial radial cross-sections of the body member and switch arms taken respectively on the lines 8-8 and 99 of Fig. 6.

In both illustrated embodiments of the invention, all elements are identical except that the switch arm members, which are identical in contour and manner of mounting, are bent so as to form a normally closed or a normally open switch assembly as desired.

The casing Hi comprises a top disc ll annularly deformed to provide a pressure compartment it. A threaded shank I3 is provided with a hole for connection to a source of fluid pressure and hard soldered into said disc II. An annular band M has at one end a flange l5 engaging the deformed rim of disc H and at the other end has a flange l6. An annular gasket insert 36.

I mounted and h f I minal members which not only fix the switch 11, preferably made of cork, lies against the inner face of the deformed rim of disc I I.

A flexible diaphragm l8 has a flange l9 fitting over a concave pressure plate 20 which is provided with a central opening. A paper disc 2| is provided with a central hole 22 and covers the other side of pressure plate 20. An actuating member 23 has a stem 24 movable within the central opening in pressure plate 20 and has a head 25. Said actuating member 23 is moulded from any suitable insulating material.

The body member 26 is also moulded from a suitable insulating material and is provided with an outer annular rim 21 for engagement by flange of band l4 whereby the aforementioned parts are assembled in fluid tight rela tionship. Said body member 26 is provided with a recess 28 which forms a switch compartment 29, which has a cylindrical side wall 30, and which has two chordal flats 3i and 32 in spaced relation therearound, see Figs. 3 and 6. Body member 23 has a central boss 33 which is provided with a bore 34 for a purpose to be later described and is provided with three equiangularly spaced holes having their centers on a circle spaced inwardly from cylindrical side wall 35. One of said holes 35, see Figs. 2 and 9, receives an insert 35 having a knurled exterior surface 3"! and a threaded hole therethrough into which is threaded an adjusting screw 38. The bottom of recess 28 may have a re-enforcing land 33, see Figs. 3, 6, '7' and 9, around said Similarly, steps or lands 43 and 4| are formed adjacent each of the chordal flats 3| and 32 and are each provided respectively with the other two holes 42 and 43 of the three equiangularly spaced holes. Preferably, the body member 26 is moulded from a black phenolic in the form just described and with the insert 33 in place and with the lands 39, 44 and 4l-and holes 42 and 43, however, other methods of producing the necessary chordal flats 3i and 32 may be used.

The mounting arrangement and formation of the switch arm members are unique and particular features of the present invention. One switch arm member 44, see Fig. 4, has a mounting portion 45 and a cantilever arm 46 extend- --ing from one end of said mounting portion 45 and having a free end carrying a contact 41. Said mounting portion 45 is crescent shaped, has an outer circular edge 43 of substantially the same curvature as cylindrical side wall 38, has a flat outer edge 43 at one end thereof, and

has a second flat outer edge 53 at the other end opposite the juncture of mounting portion 45 and cantilever arm 45. The flat outer edges 49 and 53 of mounting portion 45 are spaced apart thereon at a distance equal to the spacing of chordal flats 3| and 32, and a hole 5! is provided in one end of mounting portion 45 adjacent flat edge 49 while a larger hole 52 is provided in the other end of mounting portion 45 adjacent flat edge 52.

A second switch arm member 53, see Fig. 5,

is substantiallysemi-circular in shape, has a flat outer edge 54 at one end thereof and has a free end carrying a contact 55. A hole 56, preferably of the same diameter as hole 5! in mounting portion 45, is provided in said one end of switch arm 53 adjacent the flat outer edge 54 thereof.

The aforementioned switch arm members are eld in position by a pair of ter- .hole, of the same size as holes 56 and 42, is

'4 arm members accurately in position but also facilitate the assembly of the switch arm members within the switch compartment. For example, after coil spring 54 has been placed in bore 34, the switch arm member 44 is placed within the switch compartment 29 with the hole 5| in mounting portion in alignment with the hole 43 through land 4| and body member 26. A terminal member 5'! has a square head 58 and a stem 59 which has a threaded portion 60. The stem 59 of terminal member 51 is inserted through hole 5| in switch arm member 44 and hole 43 in body member 26 and a washer 6|, a lockwasher B2 and a nut 53 are placed on the threaded portion 60 of terminal member 51.

Abutment of the head 53 with chordal flat 32 preyentsturning of terminal member 51 during wise direction, as seen from Fig. 3, to bring outer circular edge48 and flat outer edge of the mounting portion 45, respectively, intoengagement with cylindrical side wall 30 and chordal fiat 3| thereof. At the same time, hole 52 in mounting portion 45, and which is larger than the hole 42 through land 48 and body member 25, is positioned concentrically with respect to said hole 42.

Next, an insulator member 65 provided with a i placed over hole 52 in mounting portion 45, and

the second switch arm member 53 is placed in switch compartment 29 with hole 56 in alignment with hole42 in body member 26 and with contact opposite contact 41. A second ten- .minal member 61 has a square head 58 and a stem 69 ,whichhas a threaded portion 10. The stem 69 of terminal member 31 is inserted through hole 55 in switch arm member 53, through the hole in insulator member 65, through larger hole 52 in switch arm member 44 and in concentric spaced relation thereto, and through the .hole 42 in body member 25. A washer H and lockwasher !2 are placed. over threaded portion!!! and a nut 13 is threaded thereonto.

Abutment of head 68 with chordal flat 3! prevents turning of the second terminal member .51 during tightening of nut 73 whereupon the second switch arm member 53 is secured in position with its flat outer edge 54 in engagement with chordal flat 3!, with its intermediate por- .,tion overlying adjusting screw 38, and with its I contact 55 centered with respect to contact 41 on switch arm member 44. Other washers and nuts may be placed on the terminal members for attachment of wires.

It should be noted that the terminal member 61 exerts a clamping action upon switch arm member 44 through the pressure exerted on insulator member 35 so that said switch arm member 44, which is operated by actuating member 23 and by coil spring 64, has both terminal members acting thereon to fix and maintain its position. Nevertheless, the multiple functions of terminal member 81 are accomplished without danger of short circuit because the first terminal member 51 locates switch arm member 44 so that it encircles, but is spaced from, the stem 69 and the second terminal member 61 exerts the aforementioned clamping action to insure maintaining that spaced relation.

To further facilitate mounting of the switch arm members, the terminal members may be in- "se'rted through the mounting holes therein before the switch arm members are placed in position so that mere insertion of the stems of the terminal members through the holes in the body member will bring the switch arm members into position for location by the chordal flats. This is particularly true when the stem 59 is inserted through hole 56 of switch arm member 53 and through the hole of insulator member 65 so that both parts are brought into position by insertion of the stem 69 into hole 42 in body member 25.

Final assembly is accomplished by placing the body member 26, and the parts mounted thereon or therein, within annular band I l so that rim 2! engages flange l6. Paper disc 2!, actuating member 23, pressure plate 20, diaphragm l8, gasket l! and top disc i I, carrying shank l3, are placed in the order mentioned within annular band 54 and flange I is peened over to hold all the switch parts securely in assembled relation.

The switch assembly shown in Figs. 1 and 3 is normally closed and contacts 4! and 55 are in engagement until a predetermined pressure is created in pressure compartment :2 whereupon diaphragm I8 and actuating member 23 move to displace arm 46 so that said contacts 4'! and 55 are separated. Adiusting screw 38 limits the amount that switch arm member 53 can follow displacement of arm 46 and so provides an adjustment for the pressure at which the contacts 41 and 55 are opened.

The switch assembly of the invention has an additional advantage in that it can be made as a normally open switch merely by stressing arms 46 and 53 in the opposite direction and placing the contacts on the opposite faces thereof. The normally open form of the switch assembly is shown in Figs. 6 and 7.

As shown in Fig. 7, cantilever arm 46 is stressed or bent upwardly and contact 41' is on the lower surface thereof. The second switch arm member 53, is bent downwardly, engaging the end of adjusting screw 38, and has its contact 55 on the upper surface thereof. As in the normally closed switch assembly, increasing pressure flexes the diaphragm I 8 and moves actuating member 23 which now bears against cantilever arm 46' to move it downwardly, as seen in Fig. 7, until contact 41 engages contact 55 to close the switch. Adjustment of the pressure required to close the switch contacts is still accomplished by means of adjusting screw 38 which raises or lowers switch arm member 53' and contact 55' thereon to decrease or increase, respectively, the pressure at which the normally open contacts are closed.

Since various modifications of the switch assembly are possible and will be recognized by those skilled in the art, the present disclosure is to be considered as merely illustrative and the scope of the invention is defined by the claim which follows.

Having now particularly described my invention, what I desire to secure by Letters Patent of the United State and what I claim is:

A fluid operated switch assembly comprising a casing providing a cylindrical chamber, a body member for closing said chamber and provided with a recess facing said chamber and having a cylindrical side wall, said body member being provided with three equiangularly spaced axial holes extending into said recess and having a pair of chordal flat portions each in radial alignment respectively with one of said holes, an internally threaded insert in the third of said holes, a flexible diaphragm dividing said chamber into a fluid pressure compartment and a switch compartment, a switch arm member including a mounting portion having a pair of fiat outer edges in spaced relation thereon equal to the spacing of said chordal flat portions, a terminal member extending through one of said holes in the body member and one end of said mounting portion to hold the fiat outer edges thereof against said chordal fiat portions, an actuating member between said diaphragm and said switch arm member, a semi-circular switch arm member having a flat outer edge adjacent one end thereof, a second terminal member extending through the other of the holes adjacent a chordal fiat portion of the body member and holding the flat outer edge of said semi-circular switch arm against the adjacent chordal fiat portion, the free end of said semi-circular switch arm member being in juxtaposition to the first mentioned switch arm member and an intermediate portion of said semi-circular switch arm member overly-- ing said threaded insert, and a screw threaded through said insert into engagement with said semi-circular switch arm member for adjusting the position thereof and varying the movement of the actuating pin required to operate the switch assembly.

PETER M. BYAM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,253,629 Kupferschmid Aug. 26, 1941 2,537,354 Korte et al Jan. 9, 1951 2,557,493 Andis June 19, 1951 

